Parathyroid C59 P452-458 Flashcards
(58 cards)
1
Q
ANATOMY
How many parathyroids are
there?
P452
A
Usually four (two superior and two inferior)
2
Q
ANATOMY
What percentage of patients
have five parathyroid glands?
P452
A
≈5% (Think: 5 = 5)
3
Q
ANATOMY What percentage of patients have three parathyroid glands? P452
A
≈10%
4
Q
ANATOMY What is the usual position of the inferior parathyroid glands? P452
A
Posterior and lateral behind the thyroid
and below the inferior thyroid artery
5
Q
ANATOMY
What is the most common
site of an “extra” gland?
P452
A
Thymus gland
6
Q
ANATOMY What percentage of patients have a parathyroid gland in the mediastinum? P452
A
≈1%
7
Q
ANATOMY If only three parathyroid glands are found at surgery, where can the fourth one be hiding? P452
A
Thyroid gland Thymus/mediastinum Carotid sheath Tracheoesophageal groove Behind the esophagus
8
Q
ANATOMY What is the embryologic origin of the following structures: Superior parathyroid glands? P453
A
Fourth pharyngeal pouch
9
Q
ANATOMY What is the embryologic origin of the following structures: Inferior parathyroid glands? P453
A
Third pharyngeal pouch
counterintuitive
10
Q
ANATOMY
What supplies blood to the
parathyroid glands?
P453
A
Inferior thyroid artery
11
Q
ANATOMY What percentage of patients have all four parathyroid glands supplied by the inferior thyroid arteries exclusively? P453
A
≈80%
12
Q
ANATOMY
What is DiGeorge’s
syndrome?
P453
A
Congenital absence of the parathyroid
glands and the thymus
13
Q
ANATOMY What is the most common cause of hypercalcemia in hospitalized patients? P453
A
Cancer
14
Q
ANATOMY What is the most common cause of hypercalcemia in outpatients? P453
A
Hyperparathyroidism
15
Q
PHYSIOLOGY
What cell type produces
PTH?
P453
A
Chief cells produce ParaThyroid
Hormone (PTH)
16
Q
PHYSIOLOGY
What are the major actions
of PTH?
P453
A
Increases blood calcium levels (takes from bone breakdown, GI absorption, increased resorption from kidney, excretion of phosphate by kidney), decreases serum phosphate
17
Q
PHYSIOLOGY
How does vitamin D work?
P453
A
Increases intestinal absorption of calcium
and phosphate
18
Q
PHYSIOLOGY
Where is calcium absorbed?
P453
A
Duodenum and proximal jejunum
19
Q
HYPERPARATHYROIDISM (HPTH)
Define primary HPTH.
P454
A
Increased secretion of PTH by parathyroid
gland(s); marked by elevated calcium,
low phosphorus
20
Q
HYPERPARATHYROIDISM (HPTH)
Define secondary HPTH.
P454
A
Increased serum PTH resulting from calcium wasting caused by renal failure or decreased GI calcium absorption, rickets or osteomalacia; calcium levels are usually low
21
Q
HYPERPARATHYROIDISM (HPTH)
Define tertiary HPTH.
P454
A
Persistent HPTH after correction of secondary hyperparathyroidism; results from autonomous PTH secretion not responsive to the normal negative feedback due to elevated Ca⁺ ⁺ levels
22
Q
HYPERPARATHYROIDISM (HPTH)
What are the methods of
imaging the parathyroids?
P454
A
Surgical operation
Ultrasound
Sestamibi scan
201TI (technetium)–thallium subtraction
scan
CT/MRI
A-gram (rare)
Venous sampling for PTH (rare)
23
Q
HYPERPARATHYROIDISM (HPTH) What are the indications for a localizing preoperative study? P454
A
Reoperation for recurrent
hyperparathyroidism
24
Q
HYPERPARATHYROIDISM (HPTH)
What is the most common
cause of primary HPTH?
P454
A
Adenoma ( >85%)
25
```
HYPERPARATHYROIDISM (HPTH)
What are the etiologies
of primary HPTH and
percentages?
P454
```
Adenoma ( ≈85%)
Hyperplasia ( ≈10%)
Carcinoma ( ≈1%)
26
```
HYPERPARATHYROIDISM (HPTH)
What is the incidence of
primary HPTH in the
United States?
P454
```
≈1/1000–4000
27
HYPERPARATHYROIDISM (HPTH)
What are the risk factors for
primary HPTH?
P454
Family history, MEN-I and MEN-IIa,
| irradiation
28
```
HYPERPARATHYROIDISM (HPTH)
What are the signs/
symptoms of primary HPTH
hypercalcemia?
P455
```
```
“Stones, bones, groans, and
psychiatric overtones”:
Stones: Kidney stones
Bones: Bone pain, pathologic
fractures, subperiosteal resorption
Groans: Muscle pain and weakness,
pancreatitis, gout, constipation
Psychiatric overtones: Depression,
anorexia, anxiety
Other symptoms: Polydipsia, weight
loss, HTN (10%), polyuria, lethargy
```
29
HYPERPARATHYROIDISM (HPTH)
What is the “33 to 1” rule?
P455
Most patients with primary HPTH have a
| ratio of serum (Cl⁻) to phosphate ≥33
30
HYPERPARATHYROIDISM (HPTH)
What plain x-ray findings are
classic for HPTH?
P455
Subperiosteal bone resorption (usually in
hand digits; said to be “pathognomonic”
for HPTH!)
31
HYPERPARATHYROIDISM (HPTH)
How is primary HPTH
diagnosed?
P455
Labs—elevated PTH (hypercalcemia,
↓ phosphorus, ↑ chloride); urine calcium
should be checked for familial
hypocalciuric hypercalcemia
32
HYPERPARATHYROIDISM (HPTH)
What is familial hypocalciuric
hypercalcemia?
P455
```
Familial (autosomal-dominant)
inheritance of a condition of
asymptomatic hypercalcemia
and low urine calcium, with or
without elevated PTH; in contrast,
hypercalcemia from HPTH results in
high levels of urine calcium
Note: Surgery to remove parathyroid
glands is not indicated for this diagnosis
```
33
```
HYPERPARATHYROIDISM (HPTH)
How many of the glands are USUALLY affected by the
following conditions:
Hyperplasia?
P455
```
4
34
```
HYPERPARATHYROIDISM (HPTH)
How many of the glands are USUALLY affected by the
following conditions:
Adenoma?
P455
```
1
35
```
HYPERPARATHYROIDISM (HPTH)
How many of the glands are USUALLY affected by the
following conditions:
Carcinoma?
P455
```
1
36
```
HYPERPARATHYROIDISM (HPTH)
What percentage of adenomas
are not single but found in
more than one gland?
P455
```
≈5%
37
HYPERPARATHYROIDISM (HPTH)
What is the differential
diagnosis of hypercalcemia?
P456
```
“CHIMPANZEES”:
Calcium overdose
Hyperparathyroidism (1/2/3),
Hyperthyroidism, Hypocalciuric
Hypercalcemia (familial)
Immobility/Iatrogenic (thiazide
diuretics)
Metastasis/Milk alkali syndrome (rare)
Paget’s disease (bone)
Addison’s disease/acromegaly
Neoplasm (colon, lung, breast,
prostate, multiple myeloma)
Zollinger-Ellison syndrome
Excessive vitamin D
Excessive vitamin A
Sarcoid
```
38
```
HYPERPARATHYROIDISM (HPTH)
What is the initial medical
treatment of hypercalcemia
(1 HPTH)?
P456
```
Medical—IV fluids, furosemide—NOT
| thiazide diuretics
39
```
HYPERPARATHYROIDISM (HPTH)
What is the definitive treatment of HPTH in the
following cases:
Primary HPTH resulting
from HYPERPLASIA?
P456
```
```
Neck exploration removing all
parathyroid glands and leaving at least
30 mg of parathyroid tissue placed in the
forearm muscles (nondominant arm, of
course!)
```
40
```
HYPERPARATHYROIDISM (HPTH)
What is the definitive treatment of HPTH in the
following cases:
Primary HPTH resulting
from parathyroid
ADENOMA?
P456
```
Surgically remove adenoma (send for
frozen section) and biopsy all abnormally
enlarged parathyroid glands (some
experts biopsy all glands)
41
```
HYPERPARATHYROIDISM (HPTH)
What is the definitive treatment of HPTH in the
following cases:
Primary HPTH resulting
from parathyroid
CARCINOMA?
P456
```
Remove carcinoma, ipsilateral thyroid
lobe, and all enlarged lymph nodes
(modified radical neck dissection for LN
metastases)
42
```
HYPERPARATHYROIDISM (HPTH)
What is the definitive treatment of HPTH in the
following cases:
Secondary HPTH?
P456
```
Correct calcium and phosphate; perform
renal transplantation (no role for
parathyroid surgery)
43
HYPERPARATHYROIDISM (HPTH)
Tertiary HPTH?
P457
```
Correct calcium and phosphate; perform
surgical operation to remove all parathyroid
glands and reimplant 30 to 40 mg in the
forearm if REFRACTORY to medical
management
```
44
```
HYPERPARATHYROIDISM (HPTH)
Why place 30 to 40 mg of
sliced parathyroid gland in
the forearm?
P457
```
To retain parathyroid function; if HPTH
recurs, remove some of the parathyroid
gland from the easily accessible forearm
45
```
HYPERPARATHYROIDISM (HPTH)
What must be ruled out in
the patient with HPTH from
hyperplasia?
P457
```
MEN type I and MEN type IIa
46
```
HYPERPARATHYROIDISM (HPTH)
What carcinomas are
commonly associated with
hypercalcemia?
P457
```
Breast cancer metastases, prostate
cancer, kidney cancer, lung cancer,
pancreatic cancer, multiple myeloma
47
```
HYPERPARATHYROIDISM (HPTH)
What is the most likely
diagnosis if a patient has a
PALPABLE neck mass,
hypercalcemia, and elevated
PTH?
P457
```
Parathyroid carcinoma (vast majority
of other causes of primary HPTH have
nonpalpable parathyroids)
48
PARATHYROID CARCINOMA
What is it?
P457
Primary carcinoma of the parathyroid
| gland
49
PARATHYROID CARCINOMA
What is the number of
glands usually affected?
P457
1
50
PARATHYROID CARCINOMA
What are the signs/
symptoms?
P457
```
Hypercalcemia, elevated PTH,
PALPABLE parathyroid gland (50%),
pain in neck, recurrent laryngeal nerve
paralysis (change in voice), hypercalcemic
crisis (usually associated with calcium
levels > 14)
```
51
PARATHYROID CARCINOMA
What is the common tumor
marker?
P457
Human Chorionic Gonadotropin
| HCG
52
PARATHYROID CARCINOMA
What is the treatment?
P457
Surgical resection of parathyroid mass
with ipsilateral thyroid lobectomy,
ipsilateral lymph node resection
53
```
PARATHYROID CARCINOMA
What percentage of all
cases of primary HPTH
are caused by parathyroid
carcinoma?
P458
```
1%
54
```
PARATHYROID CARCINOMA
POSTOPERATIVE COMPLICATIONS OF PARATHYROIDECTOMY
What are the possible
postoperative complications
after a parathyroidectomy?
P458
```
```
Recurrent nerve injury (unilateral: voice
change; bilateral: airway obstruction),
neck hematoma (open at bedside if
breathing is compromised), hypocalcemia,
superior laryngeal nerve injury
```
55
```
PARATHYROID CARCINOMA
POSTOPERATIVE COMPLICATIONS OF PARATHYROIDECTOMY
What is “hungry bone
syndrome”?
P458
```
Severe hypocalcemia seen after surgical
correction of HPTH as chronically
calcium-deprived bone aggressively
absorbs calcium
56
```
PARATHYROID CARCINOMA
POSTOPERATIVE COMPLICATIONS OF PARATHYROIDECTOMY
What are the signs/
symptoms of postoperative
hypocalcemia?
P458
```
Perioral tingling, paresthesia,
+ Chvostek’s sign, + Trousseau’s sign,
+ tetany
57
```
PARATHYROID CARCINOMA
POSTOPERATIVE COMPLICATIONS OF PARATHYROIDECTOMY
What is the treatment of
hypoparathyroidism?
P458
```
Acute: IV calcium
Chronic: PO calcium, and vitamin D
58
PARATHYROID CARCINOMA
POSTOPERATIVE COMPLICATIONS OF PARATHYROIDECTOMY
What is parathyromatosis?
P458
```
Multiple small hyperfunctioning
parathyroid tissue masses found over the
neck and mediastinum—thought to be
from congenital rests or spillage during
surgery—remove surgically (RARE)
```
